Flexible and curved versions of products and components that are traditionally rigid and/or planar in nature are being conceptualized for new applications. For example, flexible electronic devices can provide thin, lightweight and flexible properties that offer opportunities for new applications, for example curved displays and wearable devices. Many of these flexible electronic devices require flexible substrates for holding and mounting the electronic components of these devices. Polymeric foils have some advantages including resistance to fatigue failure, but suffer from marginal optical transparency, lack of thermal stability and limited hermeticity. When polymeric foils are employed as backplanes or substrates for electronic devices, their limited temperature resistance significantly limits processing and manufacturing of the electronic components employed in these devices.
Some of these electronic devices having static, non-planar features also can make use of flexible displays. For example, these static, non-planar features can constitute displays having beveled edges, curvature in the length direction of the device housing the display, curvature in the width direction of the device housing the display and other permutations of curved, bent or non-planar display features. Optical transparency and thermal stability are often important properties for flexible display applications. In addition, flexible displays with static, non-planar features should have high static fatigue and puncture resistance, including resistance to failure at small bend radii, particularly for flexible displays that have touch screen functionality with one or more surfaces having substantial curvature.
Conventional flexible glass materials offer many of the needed properties for substrate and/or display applications having one or more static, non-planar features. However, efforts to harness glass materials for these applications have been largely unsuccessful to date. Generally, glass substrates can be manufactured to very low thickness levels (<25 μm) to achieve smaller and smaller bend radii. However, these “thin” glass substrates suffer from limited puncture resistance. At the same time, thicker glass substrates (>150 μm) can be fabricated with better puncture resistance, but these substrates lack suitable static fatigue resistance and mechanical reliability upon bending into one or more static, non-planar shapes. In addition, some conventional glass substrate compositions have the disadvantage of containing relatively high alkali ion levels. Glass substrates made with these compositions are susceptible to alkali ion migration that can degrade the performance of the electronic devices and components mounted on these substrates.
Thus, there is a need for glass materials, components and assemblies for reliable use in backplane, substrate and/or display applications having one or more static, non-planar features, particularly for non-planar shaped electronic device applications.